Yes that's right so that some traders make multiple coins to trade for them not to lose a lot and for them also to know which coins or market value are better to trade with but if you are a trader and you only have one coin to trade then it is really up to the market now, if you are going to gain profit or not. 😁
There certainly are very little of such peoples who would just invest in one single coin and wait for it to increase up. Peoples invest in multiple coins and owning such number of coins can hardly make you have any loss. Even in times of red markets, there are some coins which are in the upward trend and holding such coin in that situation can really be a lot beneficial.
The peoples who would hold in the red markets are the ones who will have major number of profits. Even if the markets are down, you should never take your money out from it until you see the volume decreasing or the market cap going down. You should firmly stand on your decision to make you have profits.